Device and method for encoding a datum, and a device and method for decoding an encoded datum

Abstract

A device for encoding a datum, the device being operable to encode the datum by effecting a phase difference between one or more first pseudorandom signals and one or more corresponding second pseudorandom signals.

1 . A device for encoding a datum, the device being operable to encode the datum by effecting a phase difference between one or more first pseudorandom signals and one or more corresponding second pseudorandom signals.  
   
   
       2 . The device as claimed in  claim 1 , wherein the device is operable to use any one of the first pseudorandom signals as a distinct channel that can be selected to encode the datum.  
   
   
       3 . The device as claimed in  claim 1 , wherein the device is operable to use a plurality of the first pseudorandom signals as a single channel that can be used to encode the datum.  
   
   
       4 . The device as claimed in  claim 3 , wherein the device is operable to effect the phase difference by controlling a signal generating means, which is arranged to generate the first pseudorandom signals, such that it outputs a symbol of each of the first pseudorandom signals at a predetermined time, wherein the predetermined time results in the phase difference between the symbol and a corresponding symbol in each of the second pseudorandom signals.  
   
   
       5 . The device as claimed in  claim 4 , wherein the datum comprises a signal encoded with information.  
   
   
       6 . The device as claimed in  claim 5 , wherein the first pseudorandom signals and second pseudorandom signals are in the form of direct sequence spread-spectrum signals.  
   
   
       7 . A device for decoding an encoded datum, the device being operable to decode the encoded datum by determining a phase difference between one or more first pseudorandom signals and one or more corresponding second pseudorandom signals.  
   
   
       8 . The device as claimed in  claim 7 , wherein the device is operable to use any one of the first pseudorandom signals as a distinct channel that can be selected to decode the datum.  
   
   
       9 . The device as claimed in  claim 7 , wherein the device is operable to use a plurality of the first pseudorandom signals as a single channel that can be selected to decode the datum.  
   
   
       10 . The device as claimed in  claim 7 , wherein the device is operable to determine the phase difference by determining a time difference between a symbol of each of the first pseudorandom signals and a corresponding symbol of each of the first pseudorandom signals, wherein the time difference is representative of the phase difference.  
   
   
       11 . The device as claimed in  claim 7 , wherein the datum comprises a signal encoded with information.  
   
   
       12 . The device as claimed in  claim 7 , wherein the first pseudorandom signals and second pseudorandom signals are in the form of direct sequence spread-spectrum signals.  
   
   
       13 . A method of encoding a datum, the method comprising the step of encoding the datum by effecting a phase difference between one or more first pseudorandom signals and one or more corresponding second pseudorandom signals.  
   
   
       14 . The method as claimed in  claim 13 , wherein the step of encoding the datum comprises using any one of the first pseudorandom signals as a separate channel that can be selected to encode the datum.  
   
   
       15 . The method as claimed in  claim 13 , wherein the step of encoding the datum comprises the step of using a plurality of the first pseudorandom signals as a single channel that can be selected to encode the datum.  
   
   
       16 . The method as claimed in  claim 13 , wherein the step of encoding the datum is such that the phase difference is effected by controlling a signal generating means, which is arranged to generate the first pseudorandom signals, such that it outputs a symbol of each of the first pseudorandom signals at a predetermined time, wherein the predetermined time results in the phase difference between the symbol and a corresponding symbol in each of the second pseudorandom signals.  
   
   
       17 . The method as claimed in  claim 13 , wherein the datum comprises a signal encoded with information.  
   
   
       18 . The method as claimed in  claim 13 , wherein the first pseudorandom signals and second pseudorandom signals are in the form of direct sequence spread-spectrum signals.  
   
   
       19 . A method of decoding an encoded datum, the method comprising the step of decoding the encoded datum by determining a phase difference between one or more first pseudorandom signals and one or more corresponding second pseudorandom signals.  
   
   
       20 . The method as claimed in  claim 19 , wherein the step of decoding the encoded datum comprises the step of using any one of the first pseudorandom signals as a distinct channel that can be selected to decode the datum.  
   
   
       21 . The method as claimed in  claim 19 , wherein the step of decoding the encoded datum comprises the step of using a plurality of the first pseudorandom signals as a single channel that can be selected to decode the datum.  
   
   
       22 . The method as claimed in  claim 19 , wherein the step of decoding the encoded datum is such that the phase difference is determined by a time difference between a symbol of each of the first pseudorandom signals and a corresponding symbol of each of the second pseudorandom signals, wherein the time difference is representative of the phase difference.  
   
   
       23 . The method as claimed in  claim 19 , wherein the datum comprises a signal encoded with information.  
   
   
       24 . The method as claimed in  claim 19 , wherein the first pseudorandom signals and second pseudorandom signals are in the form of direct sequence spread-spectrum signals.  
   
   
       25 . Software, which when executed by a computing device, enables the computing device to carry out the method as claimed in  claim 13 .  
   
   
       26 . A computer readable medium comprising the software as claimed in  claim 25.